Word 2000

I'm working on a document with numbered sections and
appendixes.  I have no problem with the main document
since I can use the default heading styles. But I can't
get the Appendices to be properly numbered since our
format is to number them 10, 20, 30.  I tried to create
custom styles for the appendix, but the numbering will not
increment by ten.  A sample outline is:

1.0 Introduction
  1.1 Purpose
  1.2 Document Organization

2.0 Applicable Documents
  2.1 Government Documents
  2.2 Non-Government Documents

.
.
.
Appendix 10 Acronyms and Definitions
  10.1 Acronyms
  10.2 Definitions

Appendix 20 Schemas
  20.1 Schema A
  20.2 Schema B

Appendix 30 Message Formats
  30.1 Message 1
  30.2 Message 2

Of course, I also want to include the appendixes in the
TOC.

Thanks.